Thank you so much for the welcome.
You're right - I guess my brother could surprise me later on. Do you mean in terms of losing faith as well? When we last discussed this issue, my brother said he had some doubts, but has now found ways to deal with them. When I was reading The God Delusion, I discussed that with him, and he basically responded with Pascal's wager. I don't want to try to 'convince' or 'de-religionize' him, without him wanting that for himself - because all of the conflicting feelings I'm experiencing right now are so painful and I wouldn't want to force that on another person, especially someone with parents like mine.
Moving out is... a dream, unfortunately. I am a student right now but attend university in my home city. My father has made explicit that he wants me to look for a job in the same city once I graduate. I was naive enough to bring up my dream of working abroad to him once, and he said: "You can do all those things after you get married." And I felt my hopes crumble. To be honest, I don't think I ever want to marry anybody ever, but marriage is not even a potential route to more freedoms (as my father apparently wants me to see it), because he has made explicit that he would never allow me to find my own partner by way of "love affairs", and therefore I'm stuck with only very limited options. Of course my family would never consider a non-Muslim, but even marrying outside of ethnic group is hugely taboo in my household.
In fact, recently dad actually told me he would like me to get married to my first cousin. This even surprised me because dad had never directly talked to me about marriage before this. (He won't force me to accept the proposal, and that cousin-marriage discussion is 'on hold' for now, after a lot of crying on my part, but there is still emotional pressure there: 'People will think you are having love affairs in England - you have no other reason to turn this down... / What will people say about me? They will spit that I have no leverage even with my own daughter... / I know the boy well, he is my nephew, that is why I would give you to him - I cannot just give to you any other stranger who comes along after this... / I never thought that I would have to beg my child to do something. Don't you trust me?" to give a few examples.)
Working in a different city - just temporarily, if I got a placement at a particularly prestigious institution, for example - seemed like a possibility once... but I think that my parents would be extremely suspicious and unwilling to let me move away even for a short time, after recent events. Maybe, just maybe, the slim possibility of that temporary escape can be a goal I work towards in the coming years, though...
As far as just being honest with them goes, it's the death and illness thing that really scares me. My mother has depression and religion is the only thing that really gives her comfort. What if I exacerbate her mental health issues by walking out? Same with my dad. They think hell is real (and also that the opinions of 'society' matter), so if in their old age they find out they have 'failed' their child and their child is going to hell, what psychological implications might that have? I would like to say that I don't need religion to live my life in a morally sound way, but I am scared I might not be able to say that about myself if I also destroy two other lives (maybe three, my brother's) in the process of claiming mine. (This is not intended as a judgement on anyone else - just sharing what's going through my own head about myself...)
Are you in touch with family still, if you don't mind me asking?